4. OPERATIONS AND MAINTENANCE APPLICATIONS

            In order to effectively identify which ITS-generated data are relevant to operations and maintenance applications, it is important to understand the functions to which transportation operations and maintenance refer. Although “safety, reliability, and security” seem to be the terms that effectively convey the key goals of transportation operations, a clear concise definition of operations that articulates the scope and intent of the activities it comprises is being developed.^4.1

            Nonetheless, “optimizing the performance of the existing system to meet or exceed varying customer expectations under varying conditions” seems to be a reasonable objective for beginning the process of building the future of transportation operations.^4.2 To reach that objective, Dr. Johnson urged solving the four “real” transportation problems facing the nation: congestion, public safety, work zones, and weather response. Public safety refers to transportation safety and efficiency that are enabled by effective police, fire, and emergency operations. “Security” was added to the list, in response to the tragedy of September 11^th.

            The state-of-the-practice review of archiving and using ITS-generated data on operations and maintenance applications focused on data elements that have the potential to solve those aforementioned problems. This includes data generated from almost all of the nine ITS components.

4.1 STATE-OF-THE-PRACTICE REVIEW

4.1.1 Archiving and Sharing ITS-Generated Roadway/Traffic Data

            The ITS infrastructure elements pertinent to generating traffic and roadway data include: traffic signal control systems in Arterial Management Systems, Freeway Management Systems, Incident Management Programs, Transit Management Systems, Electronic Toll Collection, Advanced Rail-Highway Crossings, Regional Multimodal Traveler Information, and Emergency Response. Many of these activities are concentrated within metropolitan areas. The objectives of these deployments range from reducing congestion and delays, to providing drivers/travelers with real-time choices, to saving lives through accessible emergency response, to improving on-time transit performance.

            One hundred and six agencies responded to the Freeway Management Survey in both 1999 and 2000. Almost one in three responding agencies in 1999 did not collect any freeway data while this percentage increased to almost 40% in 2000 (Table 4.1). Data collected from this Freeway Management survey range from traffic volume, to information related to intermodal connections. By far the most commonly collected freeway data are: traffic volume, and information on scheduled work zones (Figure 4.1). The most common technique used to collect traffic data is loop detectors, followed by video imaging detectors. Figure 4.2 depicts the prominence of different techniques used to collect traffic data. It is obvious from this figure that less intrusive technologies are becoming popular in collecting traffic data. Traffic volume and vehicle classification data are the two data elements that are most likely to be archived. Eighty-seven percent of the agencies in 1999 that collected traffic volume data also archive them. And, seventy-six percent of the agencies that collect vehicle classification data also archive them (Table 4.1). The most noteworthy observation is the fewer number of agencies that generate and archive lane occupancy data, declining from 39 agencies in the year 1999 to 6 in year 2000. We speculate that data reporting errors led to the downward trend from 1999 to 2000 in terms of fewer data elements being generated and/or archived. Ramp metering has the potential to significantly reduce the traffic flow impediment. Thirty-nine of the 106 responding agencies reportedly operate entrance ramp meters within their planning boundary. However, less than one third of those agencies collect data related to ramp metering (Table 4.1).

    Table 4.1 Number of Agencies that Generated and/or Archived Freeway Traffic Data

1999 and 2000 ITS Deployment Tracking Surveys

                  * These questions were not asked in 1999

                  ** These questions were not asked in 2000

            Tables 4.2 and 4.3 show the propensity for data archiving in 1999 and 2000, with a significant downward trend. No agencies collect all seventeen data elements identified on the survey questionnaire. In 1999 one agency collected 14 of out the 17 data elements and it archived every data element collected. Overall, 31 of the 78 agencies in 1999 archived all of the traffic data collected (cells on the diagonal line) while the corresponding numbers are 19 out of 66 agencies in year 2000. In 1000 ten agencies reportedly collected traffic data but did not archive any (the “0“ column).

Table 4.2 Distribution of Agencies by Number of Data Elements Generated and Number of Data Elements Archived

1999 ITS Deployment Tracking Survey

Table 4.3 Distribution of Agencies* by Number of Data Elements Generated and Number of Data Elements Archived

2000 ITS Deployment Tracking Survey